Saves are locked to the user who created them, I believe. Either way you're probably better off just unlocking it yourself. Most of us playing this wouldn't cheapen it by allowing any random person to enjoy the things we worked for.
Saves are locked to the user account? I thought it was only for certain games? When NGSP starts off it says networking disabled or something along those lines.
I would probably feel a sense of accomplishment if I get it myself but working 2 jobs and going fulltime to school and taking care of my family takes a lot of time away. So when I do play a game I just want to enjoy it and not be stressed from the journey of obtaining a certain item in a game.
They're locked down, as I said. Not sure exactly how Sony did it but they've definitely prevented any easy method of save transferring. I can honestly say that I've never personally done it, though I do see the value in it for other people. I lead a busy life too and if going through the 20 or so hours total to get the costume is a bit much to you, nobody else has the grounds to dispute it.